Hi, I have cracked LS manifold, possibly RS too, donuts leak where Y pipe connects to manifolds and cats are leaking.
I have looked at a few sites but have not been able to find an entire kit that would work with my truck or the kits were too expensive.
I went back to the shop that had replaced my exhaust from cat back some years ago.
They gave me an estimate today of $4,230 to replace system, basically building back the way it had been; exhaust manifolds, with 2 cats, this is a lot more money then makes sense to spend on this truck.
Wanted to know if some members could make some suggestions on the best way to tackle this if I did the work myself, IE use single cat, headers instead of exhaust manifolds etc.
Maybe what other members did with their own truck or a good source(s) for replacement parts.
I don't want the truck to be too loud, and don't want to break the bank if possible. Thanks!

86 f250 302fi 4x4 4speed

estimate by Mufflex to replace exhaust

 

Forgot to mention, I plan on getting rid of the smog pump.
Found this thread on how to do >>> https://www.ford-trucks.com/forums/1...mp-delete.html

 

www.car-parts.com the junkyards may have good manifolds.

 

Being you are pulling the air pump you must not have smog check and if that is the case why buy cat(s)?
From the picture of the parts it looks like the Y pipe also had the front cat is this so or you can get the Y pipe with out the cat?

I would not go for long tube headers.
First can you find them for a 4x4 truck?
Most of the time they hang down too low.
They also leak but not sure on the short tube headers?
I believe the shorty headers work with the factory Y pipe?

So starting at the motor either factory cast manifolds or shorty headers.
Factory Y pipe hope with out the cat.
Pipe to fill the gap from Y pipe to muffler.
Could run factory replacement muffler (quite) or a performance replacement. Turbo or I run a Thrush welded muffler that is a factory replacement on my truck.
Factory tail pipe.

I would check local parts stores for price (can do this on line fore the different stores) and Rock Auto for manifolds on back to tail pipe.
I cant see going bigger on pipe size with a factory built motor so factory size pipes should work good but ........
You may want to look into larger motors in trucks and even diesels if they have larger pipes if that is the way you want to go?
I say this as not a lot has changed under the trucks over the years as the pipes all run down the right side.
Only thing you would need to deal with is the Y pipe. If you can run a factory Y pipe with out a cat then say a larger diesel pipes from there back might be the way to go? You would just need to adapt from the Y to the larger front / mid pipe.

I was lucky with my 81 F100 with a 300 six.
I run EFI EXH manifolds, they are like shorty headers but cast iron.
I run the factory Y pipe and a 94 F150 full system on back (less cat) to the tail pipe as they where bigger then the 81 pipes.
I also have a Thrush welded muffler and with the EFI manifolds I think sounds pretty good for a straight six.
Dave ----

 

My truck came with an "off road" exhaust system from LMC. Check it out.

 

Here are the exhaust manifolds. Local stores can get them for you also.

https://www.rockauto.com/en/catalog/...+manifold,5860

You can't find the y-pipe because it has the cats built into it. You need to drop back to a 1982 or so. The part you need is Walker 40279. Here it is, you can google search and find it somewhere else also.



You can see there are no gaskets. This part fits manifolds with no heat risers so make sure you buy exhaust manifolds without heat riser provision

https://www.rockauto.com/info/9/BDCN_40279_P04_FRO.jpg

Then go the store and buy a universal cat convertor. They clamp on just like a muffler. I am thinking you are 2 1/4 inch diameter coming out of the y-pipe. So you can find a short piece of 2 1/4 pipe in the store and couple the y-pipe to the cat convertor.

Here's a universal cat on amazon. I do not know if that is a typo or not, but $38 for a cat is a steal, jump on it.


This same link above also has the tailpipe and some intermediate pipes to get it all together. And you will have to get yourself a muffler.

https://www.rockauto.com/info/9/BDCN_40279_P04_FRO.jpg

 

If he is pulling the air pump then he dose not have smog check so save money and dont buy a cat just a longer pipe from the Y to the mid pipe before the muffler.
Dave ----

 

Thanks for all the posts, and information. I will post what I end up going with, and how it turns out.

 

Trying to get my ducks in row, before I find some time and start this.
Does anyone know what the torque specs should be for the exhaust manifold, and the torque sequence?
I have seen 18-24' lbs where people have recommended 20' lbs, and others have recommend 30' lbs
I have seen people recommend torque sequence from inside to outside, and others have recommended from rear to front.
I found this article that appears pretty good: https://automotorpad.com/ford/380257...ld-torque.html

 

You can always come back and add more torque if you need, I would torque to the low side...but then again, about the only things I ever torque are the lug nuts. But I'm not doing any internal engine work now day's.

 

That two step pattern makes sense to me. From the middle out. Then a straight line torque check across.

 

I never worried about exhaust manifold torque or sequence and never had any problems. You will find some of the bolt holes are tight around the bolts, and the other bolt holes are oversize around the bolts.